1. Field of the Invention
This invention relates to ligament anchor systems and devices for use in an arthoscopic surgical procedure and particularly relates to repair or replacement of a knee cruciate ligament.
2. Prior Art
In the discipline of arthoscopic knee surgery, for a particular procedure, a surgeon will form a tunnel through the tibia, intra articular joint, and femur, that is to receive an anterior or posterior cruciate ligament maintained therein. Such ligament ends can be attached, as with staples, to the femoral and/or tibial cortex surface, maintaining the ligament, under tension, across the intra articular joint. Examples of arrangements for attaching ligaments to the tibial and femoral cortexes are shown in a United Kingdom Patent, No. G.B. 2,084,468A and a patent of the present inventors, U.S. Pat. No. 4,772,286. Also a U.S. patent application, Ser. No. 246,324, of the present inventors entitled "Apparatus and Procedure for Verifying Isometric Ligament Positioning", filed Sept. 19, 1988, teaches that a ligament end can be secured to a threaded sleeve, the sleeve for turning in threads formed in a femoral or tibial cortex.
Neither the above cited United Kingdom patent, nor the earlier patent and patent application of the present inventors, however, includes a pair of longitudinally open threaded footings for turning in tunnel cortex ends and for receiving ligament mounting studs fitted therein, as does the present invention. Further, unlike earlier ligament attachment arrangements, the present invention provides for both placing a ligament and/or stint in tension between the studs, across the intra articular joint, and provides for adjusting the tension at either the femoral or tibial cortex tunnel ends.